1. Field of the Invention
The present invention relates to a head up display apparatus for an automotive vehicle such that display images from a projector is reflected from a transmittable and reflectable optical element (half-mirror) disposed on the dashboard to the driver, so that the driver can see the reflected display images (e.g. vehicle speed) in superimposition upon the vehicle outside view.
2. Description of the Prior Art
The same applicant has recently proposed a head up display apparatus for an automotive vehicle which can allowthe driver to simultaneously see the normal outside view and display images projected from a projector and reflected from a half-mirror reflector unit. However, since the driver's eye direction is different between when the vehicle is running in a city at low speed and when running on a speedway at high speed, it is necessary to adjustably pivot the half-mirror reflector unit so that the display image reflected from the reflector unit can correctly be directed toward the driver. In addition, since the driver's eye position changes according to the driver's structure of body or driver's driving position, it is also necessary to adjustably move the reflector unit up and down.
Therefore, there exists a problem in that a wide and large half-mirror reflector unit is inevitably required and therefore the driver's frontward field of view is reduced into unsafe condition.
The arrangement of the head up display apparatus for an automotive vehicle will be described in further detail with reference to the attached drawings under DETAILED DESCRITPION OF THE PREFERRED EMBODIMENTS.